Web Piracy Bill Faces Fiercer Fight

WASHINGTON—Supporters of controversial antipiracy legislation face a struggle to regain momentum after the White House sided with irate Internet companies and users over the weekend and complained that the proposal could hurt innocent companies and undermine cybersecurity.

On Saturday, the White House outlined its opposition to two similar bills pending in the House and Senate that would crack down on the sale of pirated American movies, music and other goods on foreign-based websites. The bills would require Internet...